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ISSN Druckformat: 2572-9896
ISSN Online: 2572-990X
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SELECTIVE PRODUCTION OF ALKYL LEVULINATE DIRECTLY FROM FURFURAL VIA TRANSFER HYDROGENATION OVER ZR-BASED HETEROGENEOUS CATALYSTS
ABSTRAKT
A highly efficient and selective synthesis of alkyl levulinate (AL) from furfuryl alcohol (FAL) and furfural (FUR) is demonstrated. Several acid catalysts were screened for the alcoholysis of FAL in n-BuOH. In the presence of concentrated H2SO4 and Amberlyst-15, a 90% yield of butyl levulinate (BL) was achieved. The solid acids such as Sn-Mont and Zr-Mont also showed similar activity for the alcoholysis of FAL. Different ALs were prepared in excellent yields from FAL and various alcohols using Zr-Mont catalyst. The ALs were produced selectively via one-pot conversion of FUR with alcohol using a mixture of two catalysts such as Zr-Mont and ZrO(OH)2 without using an external source of hydrogen. The transfer hydrogenation of FUR to FAL proceeded over ZrO(OH)2 using alcohol as a H donor. Then in situ formed FAL underwent acid-catalyzed alcoholysis to AL over Zr-Mont. AL was obtained in 34% yield from furfural and 2-butanol. The yield of AL was significantly increased when the reaction was performed in a 2-butanol:water mixture. The maximum of 85% yield of BL was achieved with the mixture of 2-butanol: water (85:15; v/v). In the presence of water, the rate of hydrolysis of FAL is found to be enhanced. A study of the effect of temperature on reaction and catalyst recycling was also performed.